Actually, if you're still using the same computer that you had used MPFreaker 1.0 on, all you need to do is visit http://www.lairware.com/download/ to download the latest version, then replace your old one.

MPFreaker should remember your registration code and carry on in fully licensed mode.

At any rate, as the person above mentioned you can always contact support@lairware.com and ask to have your registration code re-sent to you.